[Solved] Unreadable / distorted screen using Live CD

[RogerRoger]

Hi

I thought this would be an easy problem to find an answer to but evidently not.

I have Virtualbox 6 running on Ubuntu 18.04. I have Mint 19.? and Ubunutu 20.04 running perfectly as VMs but when I boot either from a live cd (selecting .iso) it boots but with a totally distorted and unreadable screen. I've played with various scaling settings but can't see anything else to adjust. I can boot from the live iso in a standard installation.

(forum won't let me post an image)

Any ideas?

Thanks

[mpack]

(forum won't let me post an image)

Sure it will.

Just make sure it's an image, not a link to a third party site. See the "Upload attachment" tab below the text form when composing a message.

Also attach a zipped VM log file. First make sure the VM is fully shut down, then right click it in the manager UI. Select "Show Log" and save "VBox.log" (no other file) to a zip file. Attach the zip here.

[RogerRoger]

Thanks

Log and screen grab attached (had to make the image v small to be under 128kn)

cheers

[mpack]

First of all, this site supports VirtualBox only, which you are not using. What you have there is a third party build of rather old open sources, and since we have no idea what changes might have been made, all bets are off. I recommend that you install the official version (from the downloads area here), asap.

Second, you have configured 16MB of video RAM. That is not going to please most modern graphically based OS. The VirtualBox manager will have been warning you about "invalid settings", it's best not to ignore such things. I recommend 128MB, or 256MB if you eventually enable 3D acceleration (but see next para).

In addition to third party forks of the host software, you also have third party forks of the Guest Additions, and those are even older than the host software. The GAs are what provides accelerated graphics in the guest OS. After installing VirtualBox on the host, you should update the GAs inside the guest as well. However do take note of the fact that VirtualBox 6.1.x now implements a new graphics virtual chipset for Linux guests - VMSVGA - so you should change that setting before starting the guest. The old VBoxVGA chipset will provide only basic graphics, as most of the supporting code has been withdrawn.

Oh - I would reduce main VM RAM to 6GB (6144MB), and increase the number of cores to 2.

[RogerRoger]

Thanks

After a lot of hassle getting rid of v5 and installing 6.1 (the .deb didn't work) it's worked!

Cheers

[mpack]

Thanks for reporting back.